Parenteral solutions, including fluids and blood products, or medications, often need to be applied to patients. Entry into the patient is through a cannula (blunt needle-like tube) or catheter (flexible tube), which often contains a sharp metallic or non-metallic needle for piercing skin and tissue. Once the piercing has taken place, and the cannula or catheter fixed in position, the needle can be withdrawn, and the catheter or cannula connected to other components by which fluids are introduced for therapy or diagnosis.
When a vein is to be entered, it is squeezed on its distal side to produce swelling and facilitate puncturing by a cannula or catheter contained needle, which is then removed from its cannula or catheter holder. After puncturing, it is virtually impossible to prevent an emergence of fluid, because of blood pressure, from the valve connected to the cannula. If, for example, a short catheter is introduced into a large venacava, and subsequently advanced to the venacava superior, a significant emergence of fluid cannot be prevented. In this case, an improperly placed patient, or one who makes spontaneous movements, is subject to the danger that a vacuum may occur in the punctured venacava so that air is sucked through the catheter resulting in air embolism.
In an attempt to limit the deficiencies of the prior art, U.S. Pat. No. 4,387,879 "Self-Sealing Connector for Use with Plastic Cannulas and Vessel Catheters" issued Jun. 14, 1983 to Stefan Tauschinski of Vienna, Austria discloses a connector that purports to insure that a metal cannula or vessel catheter can be pushed through the connector without obstruction, with the connector closing automatically as soon as the cannula or catheter has been disengaged. For that purpose, the connector is provided with an elastomeric disk having a central slit adjoining a slideable cylindrical member with tabs that slide within axial guide grooves of the housing. This construction is complex and costly to manufacture.
Other prior art disclosing devices with disks having central slits also are characterized by undue complexity. Thus U.S. Pat. No. 962,027 which issued to G. L. Kennedy, Jun. 21, 1910 for "Filler for Siphon Bottles" discloses a casing with a supply tube secured to one end, and a cap having an inwardly converging mouth closing the other end. A rubber gland is secured between the casing and cap, and a check valve within the casing has a hollow central conoidal portion slotted through its apex, a filling tube within the casing open at both ends, a disk secured to the tube, and a spring arranged to press the disk against the gland, with the other end of the tube extending into the hollow conoidal portion of the valve.
Another slotted-disk device characterized by undue complexity is in U.S. Pat. No. 3,570,484, issued Mar. 16, 1971 for "Intravenous Valve Assembly" to Peter Leslie Steer and Paul Hex Venn. This patent discloses devices for administering intravenous injections of liquids such as drugs, anesthetics or transfusion liquids. The device includes a valve body having a holder for an injection needle, with the holder provided with an outlet passage that communicates with the needle. A nonreturn valve is arranged in the valve body, and a valve operating plunger has a portion projecting from the body to enable the valve to be opened by operation of the plunger, which has an inlet passage through which liquid to be injected can pass from a syringe into the valve body and thence pass the nonreturn valve to the outlet passage.
Yet another slotted-disk device of undue complexity is in U.S. Pat. No. 3,848,579, issued Nov. 19, 1974 for "Automatic Elasto-Valvular Hypodermic Sampling Needle" to Antony-Euclid Villa-Real. This patent discloses a blood-drawing device with an automatically actuatable elastovalvular mechanism, sensitive to pressure differential changes, attaining variable aperture sizes in the opening phase aimed to reduce mechanical hemolysis of the red blood cells and other cellular disintegration caused by high shear forces, and, achieving a normally closed position to prevent blood drip. A valve is situated between a pair of pre-formed internal chambers that separate two axially arranged sharpened cannulas. A preferably transparent hub is provided for visual indication during extraction of singular as several separate fluid samples, such as venous blood, during a single venipuncture.
Another complex slotted-disk device is in U.S. Pat. No. 3,620,500, issued Nov. 16, 1971 for "Variable Aperture Fluid Flow Control Apparatus" to Louis S. Santomieri. This patent discloses controlling the rate of fluid flow through an intravenous infusion tube by varying the dilation of an opening in a diaphragm, and maintaining the dilation without constant attention, the dilation being controlled by the relative position of a male fitting with a female fitting.
A further complex slotted-disk device is in U.S. Pat. No. 3,601,151, issued Aug. 24, 1971 for "Nonreturn Valves for Medical Uses" to Ronald Winnard. Disclosed is a medical valve used to pass fluids into and from the body. The valve is constituted by a chamber into which a stem protrudes. The stem is provided with a bore which passes fluid into the chamber and through the valve, and acts as a seat for valve closure by an elastic-like sock which opens by expansion under pressure exerted from the stem. The valve is closed when the pressure is removed, and the sock contracts under its own elasticity around the stem. The valve can also be operated by a needle piercing the sock, which is self-sealing when the needle is removed.
Still another complex slotted-disk device is in U.S. Pat. No. 4,143,853, issued Mar. 13, 1979 for "Valve for Use With a Catheter or the Like" to Harvey J. Abramson. The disclosure is of a miniature valve for use with a catheter in which a cylindrical valve body has a male member and female member telescoped together to define opposed annular seats surrounding a through-opening. A disc of rubber having a central domed portion containing an axial slit is mounted between the seats, with the male and female members detented so that the periphery of the disc is pinched to displace rubber radially inwardly to keep the slit normally sealed against flow in either direction. The valve body has a female Luer connection adjacent the underside of the dome, and a male Luer connection adjacent the top of the dome. The female connection is spaced with respect to the disc so that when a cooperating Luer male connector is inserted into the female connection, the tip of the male connector engages the underside of the domed portion of the disc to open the slit and permit straight axial flow in either direction.
A further slotted-disk device of undue complexity is in U.S. Pat. No. 5,322,516, issued Jun. 21, 1994 for "Safety Needle System and Method For Using the Same" to James M. Brugger. A medical system is disclosed for transferring fluids (e.g. blood) to or from patients by a needle having a proximal end, a distal end attached to a syringe, a medial section, and an internal passageway. The medial section is elliptical in cross-section with dual arcuate side walls. The proximal end is blunt and rounded. Also included is an access site having a conduit with a resilient tubular port extending outwardly. The port includes a bore, and both the port and bore are elliptical in cross-section. A resilient compression member having an elliptical opening is positioned on a port to exert pressure and close the bore. In use, the needle is urged into the bore, temporarily deforming the compression member. After removing or delivering fluids using the syringe, the needle is withdrawn from the bore which is self-sealing by the compressive action.
A further slotted-disk device of undue complexity is in U.S. Pat. No. 5,322,518, issued Jun. 21, 1994 for "Valve Device for a Catheter" to Stefan Schneider, Kiel and Hans O. Maier. The disclosure is of a valve for a catheter with a hub. A tubular housing has one end with an outer cone for fitting into an inner cone of the catheter hub, and has an interior valve body acting as a locking member of an axial channel for the passage of an elongate object. The housing has an axially directed protrusion forming a radial space together with the outer surface of the outer cone. A locking member cooperates with a complementary member at the catheter hub, projecting into the space to act as a disconnection lock. The valve is for a catheter system for venous applications according to the Seldinger method, and provides sealing of the extracorporal end of the catheter.
Another complex slotted-disk device is in U.S. Pat. No. 5,322,517, issued Jun. 21, 1994 for "Disposable Automatic Hypodermic Needle Guard" to Richard C. Sircom, Yousel M. Youssef and Robert S. Solomon. Disclosed is a needle tip protecting device for hypodermic needles and catheters. The device is stored at the base of the needle prior to and during use. After use it can be slid to cover the needle tip where it automatically self-attaches and becomes non-removable.
Another slotted-disk device of complexity is in U.S. Pat. No. 4,778,453, issued Oct. 18, 1988 for "Medical Device" to George A. Lopez. Disclosed is a medical device used with a syringe that includes a needle protected by a guard. The needle has the end opposite its tip connected to the syringe. The guard is mounted on the needle and is movable axially along the shaft of the needle between a retracted position, enabling the needle to be inserted into a patient, and a forward position covering the tip of the needle. The guard is moved forward manually from the retracted to the forward position to protect against accidental needle sticks.
Another slotted-disk, complex device is in U.S. Pat. No. 5,322,515, issued Jun. 21, 1994 for "Luer Adapter Assembly for Emergency Syringe" to Peter J. Karas and Larry W. Pitts. The disclosure is of a Luer adapter assembly for a prefilled emergency syringe with a cylindrical sheath that extends coaxially with the syringe needle. The sheath can be integrally molded with the injector housing or attached to the syringe injector housing by spin welding or sonic welding. The sheath is joined to the housing so that an annual clearance space for the removable Luer adapter assembly is maintained between the tapered hub and the sheath. A removable cap on a threaded lock on the adapter extension is removed by twisting the cap in a first direction. The whole adapter assembly is removed from the tapered hub by twisting the cap is a second direction which is the same direction as the threads of the threaded lock.
Another complex, slotted-disk device is in U.S. Pat. No. 5,318,534, issued Jun. 7, 1994 for "Syringe for Balloon Catheterization" to Eli Williams and Evan Call. Disclosed is a syringe for inflation and rapid deflation of a balloon used in catheterization (transluminal angioplasty). The syringe has an actuated thread block engaged and disengaged by a rotary cam member interacting with the thread-engaging block. The block engages a threaded piston rod attached to the piston within the barrel of a balloon catheter syringe. A rotary cam engages the block to exert positive force on the block, either moving the block into a thread engaging or disengaging position. The syringe may also contain a segmented piston face so that a portion of the piston face is separately actuatable in order to introduce an increase in pressure while the main piston member remains stationary.
Other prior art which relates to connectors with elastomeric diaphragms having a central slit include Kennedy U.S. Pat. No. 962,027; Steer U.S. Pat. No. 3,570,484; Winnard U.S. Pat. No. 3,601,151; Santomieri U.S. Pat. No. 3,620,500; Villa-real U.S. Pat. No. 3,848,579 and Abramson U.S. Pat. No. 4,143,853.
Accordingly it is an object of the invention to facilitate the simplified control of fluid flow. A related object is to simplify the achievement of the "check valve" function in systems for intravenous and diagnostic therapy.